From patchwork Tue Feb 3 19:25:55 2009 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alex Williamson X-Patchwork-Id: 21783 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.176.167]) by ozlabs.org (Postfix) with ESMTP id 69CBDDDF93 for ; Wed, 4 Feb 2009 06:29:58 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752651AbZBCT2w (ORCPT ); Tue, 3 Feb 2009 14:28:52 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755895AbZBCT2v (ORCPT ); Tue, 3 Feb 2009 14:28:51 -0500 Received: from g4t0017.houston.hp.com ([15.201.24.20]:26706 "EHLO g4t0017.houston.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755834AbZBCT2s (ORCPT ); Tue, 3 Feb 2009 14:28:48 -0500 Received: from g4t0009.houston.hp.com (g4t0009.houston.hp.com [16.234.32.26]) by g4t0017.houston.hp.com (Postfix) with ESMTP id A9D8438675; Tue, 3 Feb 2009 19:28:47 +0000 (UTC) Received: from ldl.fc.hp.com (ldl.fc.hp.com [15.11.146.30]) by g4t0009.houston.hp.com (Postfix) with ESMTP id 84CD7C00A; Tue, 3 Feb 2009 19:28:47 +0000 (UTC) Received: from localhost (ldl.fc.hp.com [127.0.0.1]) by ldl.fc.hp.com (Postfix) with ESMTP id 390F839C043; Tue, 3 Feb 2009 12:28:47 -0700 (MST) X-Virus-Scanned: Debian amavisd-new at ldl.fc.hp.com Received: from ldl.fc.hp.com ([127.0.0.1]) by localhost (ldl.fc.hp.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id YVBLfYTUlwiX; Tue, 3 Feb 2009 12:28:45 -0700 (MST) Received: from debian.lart (lart.fc.hp.com [15.11.146.31]) by ldl.fc.hp.com (Postfix) with ESMTP id 8900D39C00D; Tue, 3 Feb 2009 12:28:45 -0700 (MST) From: Alex Williamson Subject: [PATCH v4 1/4] virtio_net: Add a virtqueue for outbound control commands To: rusty@rustcorp.com.au Cc: markmc@redhat.com, netdev@vger.kernel.org, kvm@vger.kernel.org Date: Tue, 03 Feb 2009 12:25:55 -0700 Message-ID: <20090203192555.2678.27075.stgit@debian.lart> In-Reply-To: <20090203192550.2678.14498.stgit@debian.lart> References: <20090203192550.2678.14498.stgit@debian.lart> User-Agent: StGIT/0.14.3 MIME-Version: 1.0 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org This will be used for RX mode, MAC filter table, VLAN filtering, etc... The control transaction consists of one or more "out" sg entries and one or more "in" sg entries. The first out entry contains a header defining the class and command. Additional out entries may provide data for the command. The last in entry provides a status response back from the command. Virtqueues typically run asynchronous, running a callback function when there's data in the channel. We can't readily make use of this in the command paths where we need to use this. Instead, we kick the virtqueue and spin. The kick causes an I/O write, triggering an immediate trap into the hypervisor. Signed-off-by: Alex Williamson Acked-by: Rusty Russell --- drivers/net/virtio_net.c | 68 ++++++++++++++++++++++++++++++++++++++++++-- include/linux/virtio_net.h | 18 ++++++++++++ 2 files changed, 83 insertions(+), 3 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 1b7e597..d31fc65 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -37,10 +37,12 @@ module_param(gso, bool, 0444); #define MAX_PACKET_LEN (ETH_HLEN + VLAN_HLEN + ETH_DATA_LEN) #define GOOD_COPY_LEN 128 +#define VIRTNET_SEND_COMMAND_SG_MAX 0 + struct virtnet_info { struct virtio_device *vdev; - struct virtqueue *rvq, *svq; + struct virtqueue *rvq, *svq, *cvq; struct net_device *dev; struct napi_struct napi; unsigned int status; @@ -605,6 +607,53 @@ static int virtnet_open(struct net_device *dev) return 0; } +/* + * Send command via the control virtqueue and check status. Commands + * supported by the hypervisor, as indicated by feature bits, should + * never fail unless improperly formated. + */ +static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd, + struct scatterlist *data, int out, int in) +{ + struct scatterlist sg[VIRTNET_SEND_COMMAND_SG_MAX + 2]; + struct virtio_net_ctrl_hdr ctrl; + virtio_net_ctrl_ack status = ~0; + unsigned int tmp; + + if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ)) { + BUG(); /* Caller should know better */ + return false; + } + + BUG_ON(out + in > VIRTNET_SEND_COMMAND_SG_MAX); + + out++; /* Add header */ + in++; /* Add return status */ + + ctrl.class = class; + ctrl.cmd = cmd; + + sg_init_table(sg, out + in); + + sg_set_buf(&sg[0], &ctrl, sizeof(ctrl)); + memcpy(&sg[1], data, sizeof(struct scatterlist) * (out + in - 2)); + sg_set_buf(&sg[out + in - 1], &status, sizeof(status)); + + if (vi->cvq->vq_ops->add_buf(vi->cvq, sg, out, in, vi) != 0) + BUG(); + + vi->cvq->vq_ops->kick(vi->cvq); + + /* + * Spin for a response, the kick causes an ioport write, trapping + * into the hypervisor, so the request should be handled immediately. + */ + while (!vi->cvq->vq_ops->get_buf(vi->cvq, &tmp)) + cpu_relax(); + + return status == VIRTIO_NET_OK; +} + static int virtnet_close(struct net_device *dev) { struct virtnet_info *vi = netdev_priv(dev); @@ -771,6 +820,14 @@ static int virtnet_probe(struct virtio_device *vdev) goto free_recv; } + if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ)) { + vi->cvq = vdev->config->find_vq(vdev, 2, NULL); + if (IS_ERR(vi->cvq)) { + err = PTR_ERR(vi->svq); + goto free_send; + } + } + /* Initialize our empty receive and send queues. */ skb_queue_head_init(&vi->recv); skb_queue_head_init(&vi->send); @@ -783,7 +840,7 @@ static int virtnet_probe(struct virtio_device *vdev) err = register_netdev(dev); if (err) { pr_debug("virtio_net: registering device failed\n"); - goto free_send; + goto free_ctrl; } /* Last of all, set up some receive buffers. */ @@ -803,6 +860,9 @@ static int virtnet_probe(struct virtio_device *vdev) unregister: unregister_netdev(dev); +free_ctrl: + if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ)) + vdev->config->del_vq(vi->cvq); free_send: vdev->config->del_vq(vi->svq); free_recv: @@ -834,6 +894,8 @@ static void virtnet_remove(struct virtio_device *vdev) vdev->config->del_vq(vi->svq); vdev->config->del_vq(vi->rvq); + if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ)) + vdev->config->del_vq(vi->cvq); unregister_netdev(vi->dev); while (vi->pages) @@ -853,7 +915,7 @@ static unsigned int features[] = { VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_UFO, VIRTIO_NET_F_HOST_TSO6, VIRTIO_NET_F_HOST_ECN, VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6, VIRTIO_NET_F_GUEST_ECN, /* We don't yet handle UFO input. */ - VIRTIO_NET_F_MRG_RXBUF, VIRTIO_NET_F_STATUS, + VIRTIO_NET_F_MRG_RXBUF, VIRTIO_NET_F_STATUS, VIRTIO_NET_F_CTRL_VQ, VIRTIO_F_NOTIFY_ON_EMPTY, }; diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h index d8e362d..245eda8 100644 --- a/include/linux/virtio_net.h +++ b/include/linux/virtio_net.h @@ -23,6 +23,7 @@ #define VIRTIO_NET_F_HOST_UFO 14 /* Host can handle UFO in. */ #define VIRTIO_NET_F_MRG_RXBUF 15 /* Host can merge receive buffers. */ #define VIRTIO_NET_F_STATUS 16 /* virtio_net_config.status available */ +#define VIRTIO_NET_F_CTRL_VQ 17 /* Control channel available */ #define VIRTIO_NET_S_LINK_UP 1 /* Link is up */ @@ -59,4 +60,21 @@ struct virtio_net_hdr_mrg_rxbuf { __u16 num_buffers; /* Number of merged rx buffers */ }; +/* + * Control virtqueue data structures + * + * The control virtqueue expects a header in the first sg entry + * and an ack/status response in the last entry. Data for the + * command goes in between. + */ +struct virtio_net_ctrl_hdr { + __u8 class; + __u8 cmd; +} __attribute__((packed)); + +typedef __u8 virtio_net_ctrl_ack; + +#define VIRTIO_NET_OK 0 +#define VIRTIO_NET_ERR 1 + #endif /* _LINUX_VIRTIO_NET_H */